Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W56/00—Synchronisation arrangements
  • H04W56/001—Synchronization between nodes
  • H04W56/0015—Synchronization between nodes one node acting as a reference for the others
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L1/00—Arrangements for detecting or preventing errors in the information received
  • H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
  • H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
  • H04L1/18—Automatic repetition systems, e.g. Van Duuren systems
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L1/00—Arrangements for detecting or preventing errors in the information received
  • H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
  • H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
  • H04L1/18—Automatic repetition systems, e.g. Van Duuren systems
  • H04L1/1812—Hybrid protocols; Hybrid automatic repeat request [HARQ]
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L5/00—Arrangements affording multiple use of the transmission path
  • H04L5/003—Arrangements for allocating sub-channels of the transmission path
  • H04L5/0044—Arrangements for allocating sub-channels of the transmission path allocation of payload
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L5/00—Arrangements affording multiple use of the transmission path
  • H04L5/0091—Signaling for the administration of the divided path
  • H04L5/0092—Indication of how the channel is divided
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W4/00—Services specially adapted for wireless communication networks; Facilities therefor
  • H04W4/70—Services for machine-to-machine communication [M2M] or machine type communication [MTC]
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W56/00—Synchronisation arrangements
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W72/00—Local resource management
  • H04W72/02—Selection of wireless resources by user or terminal
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W72/00—Local resource management
  • H04W72/04—Wireless resource allocation
  • H04W72/044—Wireless resource allocation based on the type of the allocated resource
  • H04W72/0453—Resources in frequency domain, e.g. a carrier in FDMA
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W72/00—Local resource management
  • H04W72/12—Wireless traffic scheduling
  • H04W72/1215—Wireless traffic scheduling for collaboration of different radio technologies
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W72/00—Local resource management
  • H04W72/20—Control channels or signalling for resource management
  • H04W72/21—Control channels or signalling for resource management in the uplink direction of a wireless link, i.e. towards the network
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W72/00—Local resource management
  • H04W72/20—Control channels or signalling for resource management
  • H04W72/23—Control channels or signalling for resource management in the downlink direction of a wireless link, i.e. towards a terminal
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W8/00—Network data management
  • H04W8/005—Discovery of network devices, e.g. terminals
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
  • H04W88/02—Terminal devices
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
  • H04W88/08—Access point devices
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
  • H04W88/16—Gateway arrangements
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W92/00—Interfaces specially adapted for wireless communication networks
  • H04W92/16—Interfaces between hierarchically similar devices
  • H04W92/18—Interfaces between hierarchically similar devices between terminal devices

Definitions

• the present invention relates to a wireless communication system, and more particularly, to a resource scanning method and an apparatus therefor for direct communication between terminals in a wireless communication system.
• LTE 3rd Generat ion Partnershi Project Long Terra Evolut ion
• E-UMTS Evolved Universal Mobile Telecommunication ions System
• U-TSTS UMTSCUniversal Mobile Telecom® unicat ions System
• LTE Long Term Evolut ion
• an E-UMTS is an access gateway located at an end of a user equipment (UE) and a base station (eNode B), an eNB, and an network (E-UTRAN) and connected to an external network; AG)
• a base station can transmit multiple data streams simultaneously for broadcast services, multicast services, and / or unicast services.
• the base station controls data transmission and reception for a plurality of terminals.
• the base station transmits downlink scheduling information on downlink (DL) data and informs the user equipment of time / frequency domain, encoding, data size, HARQ Hybrid Automatic Repeat and reQuest (related information), etc. .
• the base station transmits uplink scheduling information to the heading-terminal for uplink (UL) data and informs the time / frequency domain, encoding, data size, HARQ related information, etc.
• the core network may be composed of an AG and a network node for user registration of the terminal.
• the AG manages the mobility of the UE in units of a TACTracking Area consisting of a plurality of cells.
• Wireless communication technology has been developed up to LTE based on WCDMA, but the demands and expectations of users and operators are continuously increasing.
• new technological evolution is required to be competitive in the future. Reduced cost per bit, increased service availability, the use of flexible frequency bands, simple structure and open interface, and adequate power consumption of the terminal are required.
• a method of transmitting a signal using direct communication between terminals by a transmitting terminal includes a plurality of resources included in the first resource pool within a periodically defined first resource pool. Calculating a predetermined metric in units of one or more resource units for the resource units of the; Determining a transmission resource based on the calculated metric; And transmitting a direct communication signal between terminals to a receiving terminal using the transmission resource in a second resource pool after the first resource pool.
• the step of determining the transmission resource is based on the calculated metric. And determining the transmission resource for a preset processing time.
• the calculating of the predetermined metric may include calculating a predetermined metric in a bundle unit of two or more resource units for a plurality of resource units included in the resource pool.
• the predetermined metric is characterized in that the minimum or average value of the metric for each of the two or more resource units.
• the two or more resource units are characterized as being continuous on the time axis or the frequency axis.
• the calculating of the predetermined metric may include a plurality of resource units included in the third resource pool in a third resource pool located after the first resource pool and located before the second resource pool. Calculating a predetermined metric in units of one or more resource units.
• the calculating of the predetermined metric may include a final metric for the specific resource unit, the smaller of a metric for a specific resource unit of the first resource pool and a metric for the specific resource unit of the third resource pool. It may include the step of selecting.
• a terminal for performing direct communication between terminals in a wireless communication system includes: a wireless communication module for transmitting and receiving a signal with a base station or a counterpart terminal device of the direct communication between the terminals; And a processor for processing the signal, wherein the processor is a predetermined metric in units of one or more resource units for a plurality of resource units included in the first resource pool in a periodically defined first resource pool. And determine a transmission resource based on the calculated metric, and the processor transmits a direct communication signal between terminals to a counterpart terminal using the transmission resource in a second resource pool after the first resource pool. To control the wireless communication modules to be.
• the processor determines the transmission resource for a preset processing time based on the calculated metric.
• the processor may calculate a predetermined metric in a bundle unit of two or more resource units for a plurality of resource units included in the resource pool, in this case
• the predetermined metric is characterized in that the minimum or average value of the metric for each of the two or more resource units.
• the processor may further include one or more resources for a plurality of resource units included in the third resource pool in a third resource pool located after the first resource pool and located before the second resource pool.
• a predetermined metric is calculated in unit units, and a smaller value of a metric for a specific resource unit of the first resource pool and a metric for the specific resource unit of the third resource pool is selected as the final metric for the specific resource unit. Characterized in that.
• resources can be efficiently scanned for direct communication between terminals, and signals can be efficiently transmitted and received.
• FIG. 1 is a diagram schematically illustrating an E-UMTS network structure as an example of a wireless communication system.
• FIG. 2 is a diagram illustrating a control plane and a user plane structure of a radio interface protocol between a terminal and an E-UTRAN based on a 3GPP radio access network standard.
• FIG. 2 is a diagram illustrating a control plane and a user plane structure of a radio interface protocol between a terminal and an E-UTRAN based on a 3GPP radio access network standard.
• FIG. 3 is a diagram for explaining physical channels used in a 3GPP system and a general signal transmission method using the same.
• FIG. 3 is a diagram for explaining physical channels used in a 3GPP system and a general signal transmission method using the same.
• FIG. 4 is a diagram illustrating a structure of a radio frame used in an LTE system.
• FIG. 5 is a diagram illustrating a structure of a downlink radio frame used in an LTE system.
• FIG. 6 is a diagram illustrating a structure of an uplink subframe used in an LTE system.
• 7 is a conceptual diagram of direct communication between terminals.
• 8 shows an example of the configuration of a resource pool and a resource unit.
• FIG. 9 illustrates a case in which a total of four resource units are used as one bundle by using two consecutive frequency domains in two subframes according to an embodiment of the present invention.
• FIG. 10 is a diagram illustrating a process of scanning a resource pool and selecting a resource unit.
• FIG. 11 is a diagram illustrating a process of scanning a resource pool and selecting a resource unit according to an embodiment of the present invention.
• FIG. 12 illustrates an example of arranging SA resource units and data resource units according to an embodiment of the present invention.
• FIG. 13 illustrates an example of separately setting and managing SA resources and data resources according to an embodiment of the present invention.
• FIG. 14 is a diagram illustrating an operation of scanning the same resource unit in several subframes according to an embodiment of the present invention.
• 15 shows an example of setting a scan window according to an embodiment of the present invention.
• FIG. 16 illustrates a configuration example of an ON state and an OFF state according to an embodiment of the present invention.
• FIG. 17 illustrates a block diagram of a communication device according to an embodiment of the present invention.
• the present specification describes an embodiment of the present invention using an LTE system and an LTE-A system
• the embodiment of the present invention as an example may be applied to any communication system corresponding to the above definition.
• the present specification describes an embodiment of the present invention on the basis of the FDD scheme, but the embodiment of the present invention can be easily modified and applied to the H-FDD scheme or the TDD scheme as an example.
• the name of the base station includes a remote radio head (RRH), an eNB, a transmission point (TP), a receptor ion point (RP), a relay, and the like. Can be used as a generic term.
• FIG. 2 is a diagram illustrating a control plane and a user plane structure of a radio interface protocol between a terminal and an E-UTRAN based on the 3GPP radio access network standard.
• the control plane refers to a path through which control messages used by a user equipment (UE) and a network to manage a call are transmitted.
• the user plane refers to a path through which data generated at an application layer, for example, voice data or Internet packet data, is transmitted.
• the physical layer which is the first layer, provides an Informat ion Transfer Service to a higher layer by using a physical channel.
• the physical tradeoff is connected to the upper Media Access Control layer through a transport channel. Data moves between the medium access control layer and the physical layer through the transport channel. Data moves between the physical layer between the transmitting side and the receiving side through the physical channel.
• the physical channel utilizes time and frequency as radio resources. Specifically, the physical channel is modulated in the Orthogonal Frequency Division Mult iple Access (0FDMA) scheme in the downlink, and modulated in the Single Carrier Frequency Division Mult iple Access (SC-FDMA) scheme in the uplink.
• OFDMA Orthogonal Frequency Division Mult iple Access
• the medium access control (MAC) layer of the second layer provides a service to a radio link control (RLC) layer, which is a higher layer, through a logical channel.
• RLC radio link control
• the RLC layer of the second layer supports reliable data transmission.
• the function of the RLC layer may be implemented as a functional block inside the MAC.
• the Layer Data Packet Convergence Protocol (PDCP) layer of Layer 2 provides unnecessary control for efficiently transmitting IP packets such as IPv4 or IPv6 over a narrow bandwidth air interface. Perform header compression to reduce information.
• PDCP Layer Data Packet Convergence Protocol
• the radio resource control (RRC) layer located at the bottom of the third layer is defined only in the control plane.
• the RRC layer is responsible for the control of logical channels, transport channels and physical channels in association with radio bearers (RBs), conf igurat ions, re-conf igurat ions, and releases.
• RB is between the terminal and the network Means a service provided by the second layer for data transfer.
• the RRC layers of the UE and the network exchange RRC messages with each other. If there is an RRC connection (RRC Connected) between the UE and the RRC layer of the network, the UE is in an RRC connected mode, otherwise it is in an RRC idle mode.
• the non-access stratum (NAS) layer above the RRC layer performs functions such as session management and mobility management.
• One cell constituting the base station (e NB) is set to one of bandwidths of 1.25, 2.5, 5, 10, 15, 20Mhz, etc. to provide downlink or uplink transmission services to various terminals. Different cells may be configured to provide different bandwidths.
• a downlink transport channel for transmitting data from a network to a UE includes a broadcast channel (BCH) for transmitting system information, a paging channel (PCH) for transmitting a paging message, and a downlink shared cha (SCH) for transmitting user traffic or a control message. ⁇ el). Traffic or control messages of a downlink multicast or broadcast service may be transmitted through a downlink SCH or may be transmitted through a separate downlink multicast channel (MCH). Meanwhile, the uplink transmission channel for transmitting data from the terminal to the network includes a random access channel (RAC) for transmitting an initial control message and an uplink shared channel (SCH) for transmitting user traffic or a control message.
• BCH broadcast channel
• PCH paging channel
• SCH downlink shared cha
• BCCH Broadcast Control Channel
• PCCH Paging Control Channel
• CCCH Co ⁇ on Control Channel
• MCCH Multicast Control Channel
• MTCH Multicast Traffic Channel
• FIG. 3 is a diagram for describing physical channels used in a 3GPP system and a general signal transmission method using the same.
• the terminal If the terminal is powered on or enters a new cell, the terminal performs an initial cell search operation in synchronization with the base station (S301). To this end, the UE receives a Primary Synchronization Channel (P-SCH) and a Secondary Synchronization Channel (S-SCH) from the base station, synchronizes with the base station, and obtains information on the cell ID. have. After that, the terminal from the base station In-cell broadcast information may be obtained by receiving a physical broadcast channel. On the other hand, the terminal may receive a downlink reference signal (DL RS) in the initial cell search step to confirm the downlink channel state.
• P-SCH Primary Synchronization Channel
• S-SCH Secondary Synchronization Channel
• the terminal from the base station In-cell broadcast information may be obtained by receiving a physical broadcast channel.
• the terminal may receive a downlink reference signal (DL RS) in the initial cell search step to confirm the downlink channel state.
• DL RS downlink reference signal
• the UE After the initial cell search, the UE receives a physical downlink ink control channel (PDCCH) and a physical downlink ink control channel (PDSCH) according to the information on the PDCCH. Detailed system information can be obtained (S302).
• PDCCH physical downlink ink control channel
• PDSCH physical downlink ink control channel
• the terminal may perform a random access procedure (RACH) for the base station (steps S303 to S306).
• RACH random access procedure
• the UE may transmit a specific sequence to the preamble through a physical random access channel (PRACH) (S303 and S305), and may receive a voice response message for the preamble through the PDCCH and the Daesung PDSCH ( S304 and S306).
• PRACH physical random access channel
• a contention resolution procedure may be additionally performed.
• the UE After performing the procedure described above, the UE performs a PDCCH / PDSCH reception (S307) and a physical uplink shared channel (PUSCH) / physical uplink control as a general uplink / downlink signal transmission procedure.
• a physical uplink ink control channel (PUCCH) transmission (S308) may be performed.
• the terminal receives downlink control information (DCI) through the PDCCH.
• DCI downlink control information
• the DCI includes control information such as resource allocation information for the terminal, and the format is different according to the purpose of use.
• the control information transmitted by the terminal to the base station through the uplink or received by the terminal from the base station is a downlink / uplink ACK / NACK signal, CQI (Channel Quality Indicator), PMK Precoding Matrix Index (RI), RI ( Rank Indicator).
• the terminal may transmit the above-described control information such as CQI / PMI / RI through the PUSCH and / or PUCCH.
• a radio frame has a length of 10 ms (327200 x T s ) and consists of 10 equally sized subframes. Each subframe has a length of 1ms and consists of two slots. Each slot has a length of 0.5 ms (15360XT s ).
• a slot includes a plurality of OFDM symbols in the time domain and includes a plurality of resource blocks (RBs) in the frequency domain.
• TTI Transmission time interval
• the structure of the above-described radio frame is only an example, and the number of subframes included in the radio frame or the number of slots included in the subframe and the number of 0FDM symbols included in the slot may be variously changed.
• FIG. 5 is a diagram illustrating a control channel included in a control region of one subframe in a downlink radio frame.
• a subframe consists of 14 0FDM symbols.
• the first 1 to 3 0FDM symbols are used as the control region and the remaining 13 to 11 0FDM symbols are used as the data region.
• R1 to R4 represent reference signals (Reference Signal (RS) or Pi lot Signal) for antennas 0 to 3.
• the RS is fixed in a constant pattern in a subframe regardless of the control region and the data region.
• the control channel is allocated to a resource to which no RS is allocated in the control region, and the traffic channel is also allocated to a resource to which no RS is allocated in the data region.
• Control channels assigned to the control region include PCFICH (Physical Control Format Indicator CHannel), PHICH (Physical Hybrid—ARQ Indicator CHannel), PDCCH (Physical Downl Ink Control CHannel), and the like.
• PCFICH Physical Control Format Indicator CHannel
• PHICH Physical Hybrid—ARQ Indicator CHannel
• PDCCH Physical Downl Ink Control CHannel
• the PCFICH is a physical control format indicator channel and informs the UE of the number of 0FDM symbols used for the PDCCH in every subframe.
• the PCFICH is located in the first 0FDM symbol and is set in preference to the PHICH and PDCCH.
• PCFICH is composed of four Resource Element Groups (REGs), and each REG is controlled based on the Cell ID. Dispersed in the area.
• REG consists of four resource elements (REs).
• RE represents a minimum physical resource defined by one subcarrier and one OFDM symbol.
• the PCFICH value indicates a value of 1 to 3 or 2 to 4 depending on the bandwidth and is modulated by QPSKC Quadrature Phase Shift Keying.
• PHICH is a physical HARQ Hybrid-Automatic Repeat and request) indicator channel and is used to carry HARQ ACK / NACK for uplink transmission. That is, the PHICH indicates a channel through which DL ACK / NACK information for UL HARQ is transmitted.
• the PHICH is composed of one REG and is scrambled in a cell-specific manner.
• ACK / NACK is indicated by 1 bit and modulated by binary phase shi ft keying (BPSK).
• BPSK binary phase shi ft keying
• a plurality of PHICHs mapped to the same resource constitutes a PHICH group.
• the number of PHICHs multiplexed into the PHICH group is determined according to the number of spreading codes.
• the PHICH (group) is repeated three times to obtain diversity gain in the frequency domain and / or the time domain.
• the PDCCH is a physical downlink control channel and is allocated to the first n 0FDM symbols of a subframe.
• n is indicated by the PCFICH as an integer of 1 or more.
• the PDCCH consists of one or more CCEs.
• the PDCCH informs each UE or UE group of information related to resource allocation of a transmission channel (PCiKPaging channel) and DL-SCH (Downl ink-shared channel), an uplink scheduling grant, and HARQ information.
• PCiKPaging channel transmission channel
• DL-SCH Downl ink-shared channel
• PCH DL-S KDownl ink-shared channel
• the base station and the terminal generally transmit and receive data through the PDSCH except for specific control information or specific service data.
• the data of the PDSCH is transmitted to which UE (one or a plurality of UEs) and information on how the UEs should receive and decode the PDSCH data is included in the PDCCH and transmitted.
• a specific PDCCH is CRC masked with an RNTI (Radio Network Temporary Identity) called " ⁇ " and a radio resource (eg, a frequency location) called "B" and a DCI format, that is, transmission format information (eg, It is assumed that information on data transmitted using a transport block size, modulation scheme, coding information, etc. is transmitted through a specific subframe.
• RNTI Radio Network Temporary Identity
• B radio resource
• DCI format that is, transmission format information (eg, It is assumed that information on data transmitted using a transport block size, modulation scheme, coding information, etc. is transmitted through a specific subframe.
• FIG. 6 is a diagram illustrating a structure of an uplink subframe used in an LTE system.
• an uplink subframe may be divided into a region in which a Physical Upl Ink Control CHannel (PUCCH) carrying control information is allocated and a region in which a Physical Upl Ink Shared CHannel (PUSCH) carrying user data is allocated.
• the middle part of the subframe is allocated to the PUSCH, and both parts of the data area are allocated to the PUCCH in the frequency domain.
• Control information transmitted on the PUCCH may include AC / NACK used for HARQ, CQKChannel Quality Indicator indicating downlink channel status, RKRank Indicator for MIM0), SR (Scheduling Request) which is an uplink resource allocation request, and the like.
• the PUCCH for one UE uses one resource block occupying a different frequency in each slot in a subframe.
• two resource blocks allocated to the PUCCH are frequency hopping at the boundary boundary.
• 7 is a conceptual diagram of direct communication between terminals.
• an eNB may transmit a scheduling message for instructing D2D transmission and reception.
• a UE participating in D2D communication receives a D2D scheduling message from an eNB and performs a transmission / reception operation indicated by the D2D scheduling message.
• the UE means a terminal of a user, but when a network entity such as an eNB transmits and receives a signal according to a communication method between the UEs, it may also be regarded as a kind of UE.
• a link directly connected between UEs is referred to as a D2D link.
• the link in communication with the eNB is referred to as a NU link.
• the UE In order to perform the D2D operation, the UE first performs a discovery process of determining whether a counterpart UE which intends to perform the D2D communication is located in a proximity area capable of D2D communication.
• the discovery process is performed in a form in which each UE transmits its own discovery signal that can identify itself, and when the neighboring UE detects the UE, the UE transmitting the discovery signal is located in an adjacent position. That is, each UE checks whether a counterpart UE to which it wants to perform D2D communication exists in an adjacent location through a discovery process, and then performs D2D communication for transmitting and receiving actual user data.
• UE1 selects a resource unit corresponding to a specific resource in a resource pool representing a set of resources and transmits a D2D signal using the corresponding resource unit.
• the resource pool may inform the base station when the UE1 is located within the coverage of the base station. If the UE1 is outside the coverage of the base station, another base station may inform or determine a predetermined resource.
• a resource pool is composed of a plurality of resource units, and each UE may select one or a plurality of resource units to use for transmitting their D2D signals.
• FIG. 8 shows an example of the configuration of a resource pool and a resource unit.
• a resource pool is a repeat cycle ⁇ ⁇ subframe.
• one resource unit may appear repeatedly periodically.
• an index of a physical resource unit to which one logical resource unit is mapped may change in a predetermined pattern according to time.
• a resource pool may mean a set of resource units that can be used for transmission by a UE that wants to transmit a D2D signal.
• a D2D transmitting UE may calculate a metric for whether each resource unit is used in a resource pool scan process.
• This metric can be derived from the energy level measured at each resource unit. That is, if strong energy is detected in a specific resource unit, this means that the probability that the neighboring UE uses the resource unit is very high, and thus the corresponding metric may be set low.
• the metric of the resource unit having the received energy level of E mW may be given as 1 / E. Or this metric may be derived from the received power of a particular signal detected at each resource unit.
• the specific signal may be a demodulat ion reference signal (DM-RS) that is always transmitted with the D2D signal.
• DM-RS demodulat ion reference signal
• the transmitting UE selects one resource unit, it calculates a metric for each resource unit in the resource pool, 1) selects a resource unit whose metric is maximum, or 2) the metric is above a certain level ( For example, one may randomly select one of the resource units that are higher than X%), or 3) or assign a selection probability proportional to the metric to each resource unit, and then select the final resource unit according to the expansion.
• one D2D transmitting UE may need to use a plurality of resource units.
• the UE may operate to use a plurality of resource units.
• the plurality of resource units used by the UE may be a plurality of frequency domains existing in the same subframe, and in each subframe One frequency domain may be used, but may be a form spanning multiple subframes, or a complex form.
• the UE may maintain a single carrier property by using a continuous frequency domain within a subframe.
• FIG. 9 illustrates a case in which a total of four resource units are used as one bundle by using two consecutive frequency domains in two subframes according to an embodiment of the present invention.
• a separate representative metric is derived for a unit (hereinafter, referred to as a resource unit bundle) in which each resource unit having a different metric is combined into one set.
• a resource unit bundle a unit in which each resource unit having a different metric is combined into one set.
• a UE using N resource units defines N resource units as one resource unit bundle and calculates a representative metric for each resource unit bundle.
• the metric of this resource unit bundle may be determined by the method of A or B below.
• a minimum value among metrics of resource units constituting a resource unit bundle may be selected. Since even one of the resource units constituting the bundle has a low metric, there is an effect of operating the bundle itself with a low expansion when a large impact on the existing UE. If the metric of the resource unit is derived from the received energy level, it can be seen that the largest energy level among the constituting resource units regards the received resource unit as the representative resource unit of the bundle.
• An average value of the metrics of resource units constituting the resource unit bundle may be selected. This has the effect of using the bundle with a certain probability if the other resource unit is very appropriate even if it is used by another UE in the specific resource unit constituting the bundle.
• the mean value here can be either the arithmetic mean of the metric but in the form of a geometric mean or harmonic mean.
• the concept of a resource unit bundle may be characterized only when occupying different frequencies of the same subframe. This means that even if the UE uses two resource units located in different subframes at the same time, While there may be no restriction in the combination, when two resource units located in the same subframe are used at the same time, there is a restriction that the adjacent resource unit should be selected for the above reason.
• a resource unit having a very low metric is not always selected. That is, when the metric of a specific resource unit or resource unit bundle falls below a certain level, the corresponding resource unit is not selected in any case. If this metric is determined from the energy level received at each resource unit, this may appear to be forbidden to use for resource units with energy levels above a certain level. Therefore, if the metric is lower than the reference value in all resource units in the resource pool, the UE should delay transmission and wait until a valid resource unit is created.
• the criterion of the metric used herein may be a predetermined value or may be notified by an eNB or another UE by specifying an appropriate value.
• FIG. 10 is a diagram illustrating a process of scanning a resource pool and selecting a resource unit.
• FIG. 10 it is assumed that subframes to which one logical resource unit is mapped are the same.
• FIG. 11 is a diagram illustrating a process of scanning a resource pool and selecting a resource unit according to an embodiment of the present invention.
• FIG. 11 shows resources located at different periods. An example of using the unit in one scan is shown.
• a scan for the last X subframes is not directly performed but a subframe. Scan to the same logical resource unit located before # 0, and operate to assume that the result is maintained in the last X subframes. Accordingly, even when selecting a resource unit that appears first in a specific period, a processing time of at least X subframes is guaranteed.
• X may be determined as three subframes that determine the relationship between the scheduling of the LTE and the UE transmission.
• the result of one scan period (or one resource period) is applied to the selection of the resource unit.
• the result of the corresponding scan cycle is applied until the next resource unit.
• the structure in which the processing time between the scan and the selection of the resource unit described in FIG. 11 exists may be effectively used even when the UE receives the D2D signal.
• this operation will be described in detail.
• the D2D receiving UE may perform a series of scan operations before receiving a full-scale D2D data channel transmitted from the D2D transmitting UE. This is to determine which resource unit each D2D transmitting UE uses which parameter (eg, a modulated ion and coding scheme (MCS) used for a data channel). For this purpose, the D2D transmitting UE may apply some D2D resource units to transmit resource unit information and parameters used by the D2D receiving UE, and the D2D receiving UE scans these resource units and grasps related information.
• MCS modulated ion and coding scheme
• a signal for transmitting a resource unit and a parameter used by a D2D transmitting UE in a data channel may be called a scheduling assignment (SA), and only some of the entire D2D subframes may identify an SA in order to reduce overhead caused by the SA. Can be used as a resource unit for.
• the D2D receiving UE needs to scan the resource unit to which the SA can transmit, identify the resource unit to which the data channel is transmitted and the parameters to apply, and then receive it by itself. The receiving operation is selectively performed only on the data resource unit. In this case, the D2D receiving UE needs a time to scan the SA and selects a data resource unit for receiving through the processing time.
• FIG. 12 illustrates an example of arranging SA resource units and data resource units according to an embodiment of the present invention.
• y consecutive subframes are used as the SA resource unit, and the scan operation is reflected in the resource selection after the processing time of the X subframe.
• the above-described concept may be extended for securing processing time in the D2D transmitting UE side, unlike securing the processing time in the D2D receiving UE side described above.
• the SA transmitted from another UE may be scanned in advance, and as a result, processing time may be required for resource determination for own data transmission.
• the SA may be pre-scanned from the other UE to obtain information such as the location of the resource to be used by the other UE, and the above-described metric may be defined and the resource to be used for its own transmission may be selected.
• the D2D data transmitted by the D2D transmitting UE that scans the SA of another UE and then performs transmission is a data transmission without an SA.
• a resource unit particularly a subframe, may be separately configured and managed in an SA resource and a data resource.
• the scan information obtained from the series of SA resources is applied to the series of data resources.
• scan information obtained from an SA resource may be applied from a data resource appearing after an X subframe which is a processing time from the last subframe among the corresponding SA resources.
• FIG. 13 illustrates an example of separately setting and managing SA resources and data resources according to an embodiment of the present invention. In particular, FIG.
• an SA in subframe # 0 and subframe # 1 may be applied to data from subframe # 5, and an SA in subframe # 10 and subframe # 11 may be used in subframe # 11. It can be seen that it is applicable to data from 15.
• subframe # 12 subframe # 13, and subframe # 14, although SA is closer to the previous (i.e., subframe # 10 and subframe # 11), the processing time is not divided, so the earlier (Subframe # 0 and Subframe # 1)
• the parameter to be applied is determined by the SA.
• the data resource is selected by applying scan information from the data resource appearing after the X subframe, which is a processing time, from the last subframe among the corresponding SA resources, but no longer after the time when the next SA resource appears. Will stop. For example, when a resource is configured as shown in FIG. 13, the scan result in subframes 0 and 1 is applied only to subframes # 5, # 6, # 7, # 8, and # 9. If such an operation is performed, subframes having an interval within the processing time with the SA subframe, for example, subframes # 2, # 3, # 4, # 12, # 13 and # 14 in FIG. It can be defined that data transfer is impossible.
• SA resource subframes are not necessarily continuous. It may be discontinuously located. In the case of discontinuous positioning, subframes not used for D2D communication may be located between SA subframes. If the D2D data resource subframe is located, the data subframe may be parameterized by the SA resource set in the previous period according to the above-described rule. Alternatively, in order to prevent an operation of mixing the SA and the data subframes in advance, a D2D data subframe associated with the corresponding SA may not be positioned between two subframes belonging to one SA resource set. In other words, a series of consecutive D2D subframes constitute a set of SA resources.
• NT subframes corresponding to one period are scanned.
• the present invention is not limited thereto, and a larger number may be used for a more accurate scan of resource units. It may also scan for the previous subframe of.
• different metrics may be measured at each time even for the same logical resource unit, and the metrics of the resource unit bundles described above may be used to measure the metrics of individual physical resource units for the same logical resource unit, respectively. Operate to calculate a metric of a logical resource unit.
• the highest energy level is received as a result of scanning the same resource unit in several subframes. Can be taken as the representative metric of the resource unit.
• the operation of scanning the same resource unit in multiple subframes may be performed even when low energy is detected in the corresponding resource unit because there is no data to be temporarily transmitted by the UE that performs communication, or energy is received because the corresponding channel is temporarily worsened. It can be assumed that the resource is empty to prevent the occurrence of a stratification.
• FIG. 14 is a diagram illustrating an operation of scanning a same resource unit in several subframes according to an embodiment of the present invention.
• the resource pool is scanned for two periods, and for the resource unit # 0, although low energy is detected in one period, high energy is generated in another period. Since it is detected, the metric for selecting the lowest metric is set to a low metric for the resource unit, and is operated as unusable as possible.
• a medium metric may be allocated to resource unit # 0 in the case of FIG. 14.
• interference may occur if the legacy UE temporarily uses resource unit # 0.
• the legacy UE terminates communication and no longer uses resource unit # 0, the resource unit may be used soon. This has the advantage of increasing the likelihood.
• Scan Window is the length of the offset of the X sub-frame by sub-frame for ⁇ ⁇ is the processing time corresponding to the period of the resource pool is on.
• the scan window has a length of 2 * ⁇ ⁇ subframes without an offset.
• the length of the scan window described above may be fixed for convenience of operation, but may be adjusted according to a series of rules in order to adapt to a dynamically changing situation.
• the length of the scan window may be adjusted according to the length of time when the transmitting UE stops transmitting the D2D signal.
• the D2D UE cannot receive another signal at the time when the D2D UE transmits a signal, because its own transmission signal acts as a strong interference to the received signal.
• a specific D2D transmitting UE selects a specific resource unit and transmits a D2D signal, it means that a scan for a resource unit located in the same subframe as the corresponding resource unit is impossible. Therefore, in order to scan each resource unit in the same period, the above-described scan window does not allow the UE to transmit a D2D signal. Can only be set at this point.
• traffic generated to an individual UE has a characteristic of being random according to time, for example, a large amount of traffic occurs at a specific time, but no traffic occurs at another time. Even if the UE selects a specific resource unit repeated in the NT subframe and transmits the D2D signal, there is a case in which a signal is not transmitted because there is no more traffic to transmit at a specific time. For convenience, if the UE is transmitting a D2D signal in a specific resource pool period, the UE is referred to as being in an ON state, and if the UE is not transmitting a D2D signal in a specific resource pool period, the UE is referred to as being in an OFF state.
• the specific UE transmits the D2D signal while passing through the ON state and the OFF state.
• the scan window of a specific UE may appear only when the UE is in the OFF state, and for more accurate scanning, the scan window may be adjusted to adjust the length of the scan window according to the length of time that the UE stays in the OFF state. .
• the length of the scan window may be set to one of 0 and a specific number A greater than zero.
• the length of the scan window is A means that the scan window has a length corresponding to A times the resource pool period, that is, an A * N T subframe.
• the length of the time remaining in the OFF state as a criterion for selecting one of 0 and A may be greater than or equal to a specific reference value, so that the length of the scan window may be A.
• the reference value may be an A period, and if a constant processing time is required as shown in FIG. 11, the reference value may be (A + 1) period.
• the accuracy of the resource scan result is affected by the length of the scan window due to the channel change and the presence of noise components, and at least a constant scan window is required to obtain a scan result of sufficient accuracy. It may be a value corresponding to a minimum constant scan window length.
• the length A scan is sufficient because a particular UE stays in the OFF state. If shadow setup is possible, the UE may perform such resource scan and select a resource unit to use in the next ON state according to the principles described above. On the other hand, if the UE cannot stay in the OFF state and the scan window of length A cannot be set, the stable scan is not possible during the period. Therefore, the scan window is not set, that is, the length is set to 0 and a new scan is performed. It works so as not to. In this case, the resource to be used in the next ON state can be determined by maintaining the scan result that was previously stable, and in other words, it can be regarded as maintaining the existing resource as it is.
• the scan state of length A may be further maintained for some time. Makes it configurable and thereby operates to transmit the D2D signal using the newly determined resource unit.
• this behavior is such that the time the UE stays in the OFF state, even if it does not meet the baseline, is close to, for example, the amount of time required to reach the baseline is below a certain level, so that the scan window of length A with only a few additional OFF states is required. It can optionally be performed in a setting possible situation.
• the scan window may appear in a form in which the length is maintained or increased as the duration of the UE staying in the OFF state increases.
• a certain limit may be applied to the maximum length of the scan window to exclude this.
• the scan window setting if a certain condition is satisfied, even if it is in the 0N state, it may be prescribed to forcibly move to the OFF state to perform a resource scan. More specifically, if the UE stayed in the 0N state continuously for M periods, the UE may be moved to the OFF state for at least a predetermined time to perform the above-described resource scan.
• An OFF state stay for a time during which the minimum length of the scan window cannot be set can still be regarded as staying in the ON state. This is because the basic reason for performing the operation is to prevent a particular UE from staying in the ON state for too long, losing the opportunity to scan the communication environment and continuing to use inappropriate resources.
• FIG. 15 illustrates an example of setting a scan window according to an embodiment of the present invention.
• FIG. 15 assumes that the resource scan is possible when the cycle M corresponds to 6 and there is an OFF state for at least two cycles.
• the UE has been in the OFF state for one period after being in the 0N state for four periods. However, it is assumed that six 0N states are contiguous and then moved to the OFF state for two cycles. To do.
• the UE may operate to move to the OFF state in advance and set the scan window before the 0N state for M periods consecutively occurs.
• this operation may be defined in the form of "the time at which a particular UE may stay in the OFF state for a certain time in succession and subsequently in the 0N state is less than or equal to M periods.”
• FIG. 16 illustrates a configuration example of a 0N state and an OFF state according to an embodiment of the present invention.
• the D2D UE performs a resource scan before the M cycles of 0N states in succession occur while increasing the probability of switching to the OFF state as the number of times it stays in the 0N states continuously increases. To operate. In this case, the probability of moving to the OFF state is 1 when MN consecutive 0N states occur. It is possible to set.
• the UE continuously performs a secondary scan operation in a subframe not transmitted by the UE. If a situation change of more than a certain level is detected, the mobile station may move to the OFF state to perform a full scan operation and a resource unit selection operation.
• the transmitting UE may perform a scan operation in a subframe in which the transmitting UE does not transmit the D2D signal. Therefore, even if only a subframe that does not transmit the D2D signal is performed a continuous scan (called the secondary scan), if a certain level of change is observed in the scan result, the UE can identify this as a significant change in the communication situation. .
• the significant change may exemplify the movement of the UE, participation in transmission of a new UE, or interruption of transmission of an existing UE.
• the window length of the secondary scan is longer than the length of the scan window for the selection of the resource unit.
• the value measured through the secondary scan may also be the same as the energy level in each resource unit or the received power of a specific signal such as DM-RS in each resource unit.
• the measurement value in a particular resource unit increases or decreases by more than X%, it may be determined that a change is observed in that resource unit. In other words, if a change is observed in y 3 ⁇ 4 or more of the total measured resource units, it may be regarded as a change in the communication environment and operated to move to the OFF state.
• a representative value in all measured resource units is defined, for example, the maximum or minimum value of the measured value in each resource unit, or the average value, then the value is increased or decreased by more than X%, It may be regarded as a change, and may operate to move to the OFF state.
• the D2D transmitting UE detects a synchronization reference signal transmitted by an eNB or another UE, synchronizes time and / or frequency thereto, and then transmits a D2D signal, but the UE transmits the D2D signal due to a movement of the UE.
• the synchronization criteria may be changed to another eNB or another UE.
• the continuous synchronization reference signal transmission of the UE may be terminated and the other UE may operate to transmit the synchronization reference signal.
• the D2D transmitting UE regards this as a change in the communication environment and moves to the OFF state (that is, temporarily suspends transmission of the D2D signal), performs a resource scan, and then Operate to reselect the unit.
• the time at which the UE stays in the OFF state may be randomly determined. This is to prevent occurrence of stratification in the selected resource unit by all UEs simultaneously transmitting signals at the same time. For example, if the synchronization criteria are changed, each UE stays in the OFF state for at least a certain amount of time and performs a resource scan, but the length of time in the OFF state is randomly determined so that the UEs sequentially transmit D2D signals. Can be.
• UEs staying longer in the OFF state may first operate to detect a signal of the UE moving to the 0N state and perform its own resource unit selection based on this.
• a criterion for determining whether each resource unit is occupied by an existing UE through a resource scan will be described in detail.
• the UE may determine whether each resource unit is occupied by an existing UE in performing a resource scan.
• the resource unit determines that an existing UE is using and gives a low metric (eg, 0). On the other hand, if less than a certain level of energy is detected, the resource unit is determined to be empty and can be given a high metric (eg, 1). Through this process, it is possible to determine which resource unit is empty and, when entering the ON state, operate to use the resource unit determined to be empty.
• a random backoff process may be considered. Specifically, the UE generates one random number within a certain range and initializes the backoff counter. If after, to reduce the back-off counter by the number of resource units in each blank subframe backoff counter is zero, the graphite is less, it may be defined to D2D transmit the signal, and. Even in this case, it is necessary to determine whether the resource unit is used by another UE.
• whether or not the resource unit is empty may be determined whether the energy detected from the resource (or the received power of a specific signal such as DM—RS) exceeds a predetermined reference value.
• a specific signal such as DM—RS
• power transmission due to the transmitted signal also appears in other frequency domains (ie, other resource units). This is referred to as in-band emission.
• a reference value for determining whether the Daron resource unit of the same subframe is empty Is set relatively higher than the reference value used in other subframes.
• the reference value of whether each resource unit is empty in each subframe may be determined by the maximum received energy detected in the resource unit of the same subframe. For example, assuming that the maximum received energy detected in the resource unit of subframe #n is E n (W), the unused determination criterion in each resource unit of subframe # 1 is max (a * E n> b) (It can be ⁇ , where a is a coefficient that sets the reference value proportional to ⁇ , and b is the minimum value of the non-use determination criterion value. It is possible to more accurately determine whether each resource unit is empty.
• FIG. 17 illustrates a block diagram of a communication device according to an embodiment of the present invention.
• the communication device 1700 includes a processor 1710, a memory 1720, an RF module 1730, a display module 1740, and a user interface modules 1750.
• the communication device 1700 is shown for convenience of description and some models may be omitted. In addition, the communication device 1700 may further include the necessary modules. In addition, some of the hairs in the communication device 1700 can be divided into more granular hairs.
• the processor 1710 is configured to perform an operation according to an embodiment of the present invention illustrated with reference to the drawings. Specifically, the detailed operation of the processor 1710 is described with reference to FIGS.
• the memory 1720 is connected to the processor 1710 and stores an operating system, an application, a program code, data, and the like.
• RF mod 1730 It is connected to the processor 1710 and performs a function of converting a baseband signal into a wireless signal or converting a wireless signal into a baseband signal. To this end, the RF modules 1730 perform analog conversion, amplification, filtering and frequency up-conversion or their reverse processes.
• Display modules 1740 are connected to the processor 1710 and display various information.
• the display module 1740 may use well-known elements such as, but not limited to, LCDCLiquid Crystal Diplay (LCD), Light Emitting Diode (LED), and 0rganic Light Emitting Diode (0LED).
• the user interface models 1750 are connected to the processor 1710 and can be configured with a combination of well known user interfaces such as a keypad, touch screen, and the like.
• a specific operation described in this document to be performed by a base station may be performed by an upper node in some cases. That is, it is obvious that various operations performed for communication with the terminal in a network including a plurality of network nodes including a base station may be performed by the base station or other network nodes other than the base station.
• a base station may be replaced by terms such as fixed station, Node B, eNode B (eNB), access point, and the like.
• An embodiment according to the present invention may be implemented by various means, for example, hardware, firmware, software, or a combination thereof.
• Applic icat ion speci f ic integrated circuits ASICs
• DSPs digital signal processors
• DSPDs digital signal processing devices
• PLDs programmable logic devices
• FPGAsCf ield programmable gate arrays FPLDs
• processors controllers
• controllers It may be implemented by a microcontroller, a microprocessor, or the like.
• an embodiment of the present invention may be implemented in the form of a module, a procedure function, or the like for performing the functions or operations described above.
• the software code may be stored in a memory unit and driven by a processor.
• the memory unit may be located inside or outside the processor, and may exchange data with the processor by various known means.

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